Any animal that goes outside is susceptible to catch fleas, unless they are using a prevbentive treatment such as advantage or revolution.
I was told that if his dog got fleas, it's his own fault for not treating it proper.
I also told the vet that I have been feeding and sheltering strays for 4 years now, where I'm at, and never did the guy complained about fleas.
I was told the dog going outside unprotected was going to catch fleas one day or another.